Catecholamin-stimulated adenylate cyclase activity requires that Beta-adrenergic receptors interact with the protein components of adenylate cyclase in an appropriate membrane structure. In order to study this interaction, model reconstituted systems will be developed in which receptor, enzyme, and the lipid composition of the membrane can be manipulated independently. Beta-adrenergic receptors solubilized from S49 lymphoma cells and other sources will be incorporated into receptor-deficient plasma membranes in an attempt to reconstitute hormonal regulation of enzymatic activity. Such a system will permit direct studies of receptor-enzyme interaction and will be the basis of an assay for receptor function beyond binding of hormones. It will also allow the detection of any receptor-associated "coupling factor" which may be assayable only by their reconstitutive activities. Solubilized receptors will also be reconstituted into monolamellar lipid vesicles as a prelude to the reconstitution of both receptor and enzyme into a defined lipid environment. In this system, the effects of individual lipids and general physical properties of the bilayer on the incorporation of receptors into the vesicles and on their ligand-binding properties will be evaluated. Similar studies on the incorporation of the catalytic protein of adenylate cyclase into lipid vesicles will also be initiated. Techniques will be developed for the substitution of plasma membrane lipids with exogenous lipids in order to study their effects on an intact, functional adenylate cyclase system. These studies will provide necessary background information for future reconstitution experiments and will also demonstrate any direct effects of lipids on ligand binding to the receptor, enzymatic activity, and its regulation by the receptor-hormone complex.